U.S. Pat. No. 5,932,955 has already disclosed a lamp which is closed on two sides and in which two cap parts have contact elements which are seated in tubular extensions at the end of pinches which are responsible for sealing. The contact elements extend transversely with respect to the lamp axis and are surrounded by the tubular extensions as sleeves. Securing is effected along the circumference of the contact elements. One drawback of this is that the contact elements can easily become tilted, and consequently they are no longer positioned exactly transversely with respect to the lamp axis and, moreover, the risk of fracturing is relatively high.